Surgical procedures on the eye have been on the rise as technological advances permit for sophisticated interventions to address a wide variety of ophthalmic conditions. Patient acceptance has increased over the last twenty years, as such procedures have proven to be generally safe and produce results that significantly improve patient quality of life.
Cataract surgery remains one of the most common surgical procedures, with over 16 million cataract procedures being performed worldwide. It is expected that this number will continue to rise as average life expectancies continue to increase. Cataracts are typically treated by removing the crystalline lens from the eye and implanting an intraocular lens (“IOL”) in its place. Conventional IOL devices typically provide vision correction at only a single distance via a monofocal lens, and thus fail to correct for presbyopia. Accordingly, while patients who undergo a standard IOL implantation no longer experience clouding from cataracts, they are unable to accommodate, or change focus from near to far, from far to near, and to distances in between, and still require use of corrective glasses.
Surgeries to correct refractive errors of the eye have also become extremely common, of which LASIK enjoys substantial popularity with over 700,000 procedures being performed per year. Given the high prevalence of refractive errors and the relative safety and effectiveness of this procedure, more and more people are expected to turn to LASIK or other surgical procedures over conventional eyeglasses or contact lenses. Despite the success of LASIK in treating myopia, there remains an unmet need for an effective surgical intervention to correct for presbyopia, which cannot be treated by conventional LASIK procedures.
As nearly every cataract patient also suffers from presbyopia, there is convergence of market demands for the treatment of both these conditions. Various modifications of IOL devices have been introduced to address ophthalmic cataracts and/or presbyopia in patients. For instance, multifocal lenses for IOL devices were introduced to provide vision correction at more than one distance with the goal of obviating the need for additional corrective lenses required with the monofocal lenses. Multifocal lenses generally have areas of varying refractive power to provide vision at multiple distances (e.g., near, intermediate and far). However, one significant disadvantage to multifocal lenses is the possibility of visual distortions, particularly in the form of glare and halos around light sources at night.
Accommodating IOL devices have also been recently introduced for use in cataract surgery. Accommodating IOL devices often feature a monofocal lens configured to move and/or change shape in response to the eye's natural mechanism of accommodation, thereby providing vision correction over a broad range of distances. Such accommodating IOL devices may also feature a haptic system protruding from the central lens. Such haptic systems are typically configured to respond to the contraction and relaxation of the eye's ciliary muscles and ultimately effect changes in the central lens to provide varying diopters of power.
Some IOL devices may also include a fluid therein, where the movement of said fluid may result in an optical power change. However, conventional fluids have been found to lead to undesirable swelling of the bulk polymer material(s) comprising the IOL device (e.g., the lens, the haptic system, etc.). There is therefore a need to develop improved fluids for use in IOL devices that minimize or eliminate the swelling of the bulk polymer material(s) of said devices.